Spindle for spinning or twisting machines

ABSTRACT

A spindle with a common housing for the collar bearing and footstep bearing of the rotatable center shaft in which the footstep bearing is provided with centering means which counteract the deflections of the lower end of the center shaft and comprise a tube of plastic of a certain inherent resilience in the lower end of which at least the part of the footstep bearing is mounted which is subjected to radial pressures of the lower end of the shaft, while its upper end is mounted in the housing underneath the collar bearing so that the lower end is resiliently pivotable either due to the resilience of the tube when its upper end is rigidly secured to the housing or due to a so-called basket spring acting upon the lower end of the tube when the upper end of the latter is pivotably mounted in the upper part of the housing. These centering means further comprise suitable resilient damping means of a conventional type, for example, an oil-immersed coil spring, which act upon the lower part of the plastic tube.

United States Patent 1m Stahlecker 1 1 Jan. 1, 1974 [5 SPINDLE FOR SPINNING OR TWISTING Primary Examiner-John Petrakes MACHINES Attorney-Craig 8L Antonelli [75-] Inventor: Fritz Stahlecker, Bad Ueberkingen,

Germany [57] ABSTRACT 7 Assighee; sp h'jjf iifih's' im A spindle with a common housing for the collar bear- Stahlecker & n GmhbJ-L, ing and footstep bearing of the rotatable center shaft Suessh, Gel-many in which the footstep bearing is provided with centering means which counteract the deflections of the [22] F'led: 1971- lower end of the center shaft and comprise a tube of 21 APPL 07 93 plastic of a certain inherent resilience in the lower end of which at least the part of the footstep bearing is mounted which is subjected to radial pressures of the [52] US. Cl 57/135, 308/149, 308/155 lower end of the Shaft while its upper end is mounted [51] [1 11. CI DOlh 7/12 in the housing underneath the collar bearing so h [58] Fleld of Search the lower end is resiliently pivotable either due to h 57/129435; 308/149. 156 resilience of the tube when its upper end is rigidly secured to the housing or due to a so-called basket [56] References Cmid spring acting upon the lower end of the tube when the UNITED STATES PATENTS upper end of the latter is pivotably mounted insthe 2.946.179 7/1960 Kodama 57/135 X pp P Of the housing- These Centering means 3.019.591 2/1962 Cortabarria 57/135 ther comprise suitable resilient damping means of a 3.065.593 11/1962 Westall et alm. 57/l35 conventional type, for example, an oil-immersed coil 3976306 2/19153 Wagn 11 .5 spring, which act upon the lower part of the plastic 3,354 629 11/1967 Schmid 57/135 tube 3,410,075 11/1968 Stahlccker 57/135 12 Claims, 9 Drawing Figures PATENTED JAN 1 [974 INVENTOR FRITZ STAH LECKER BY Craig, Afltoneul, SlieLdQJ'lZ ATTORNEYS SPINDLE FOR SPINNING OR TWISTING MACHINES The present invention relates to spindles for spinning or twisting machines and more particularly to the bearing structure for the rotatable center shaft of such a spindle which comprises a bearing housing and a collar bearing, preferably in the form of a roller bearing, and a footstep bearing for the center shaft mounted within the housing, and wherein at least the part of the footstep hearing which is subjected to the radial pressures of the lower end of the center shaft is mounted in a tube the lower part of which is radially movable and which extends up to a position near the collar bearing where this tube is guided in radial directions, and wherein suitable damping means which are preferably effective in radial directions of the center shaft are interposed between this tube and the bearing housing in which both the collar and footstep bearings are mounted.

When a cop is being built up on a spindle of a spinning or twisting machine, unbalancing forces usually occur which tend to pivot the rotating center shaft about the collar bearing. in order to attain a proper rotation of the center shaft, these pivoting movements or vibrations must not only be damped, but the bearings of the center shaft must also be capable of very accurately centering the latter.

The prior art discloses centering means comprising a steel tube the upper end of which is clamped in a fixed position 'while its lower end contains a footstep bearing for the center shaft, and which for the purpose of restoring the center shaft to its centered position is made slightly resilient by being provided with slots or apertures or by being made of a varying cross section. The degree and uniformity of the centering effect of such tubes depend upon the shape and dimensions of the slots or apertures or the shape of the tubes. It has now been found that, when the spindle is subjected to certain load conditions, such a centering tube which is made of steel will be affected by vibrations which may considerably impair the proper rotation of the spindle, and that it is either impossible or at least very difficult to influence or control these vibrations in such a manner by or in cooperation with the damping means as may be provided that they will no longer cause any difficulties. These steel tubes have the further disadvantage that their manufacture is very expensive. It is also very difficult and expensive to assemble them together with the collar bearings and the footstep bearings so as to form structural units, especially since very small tolerances are required between the elements of such a unit.

It is an object of the present invention to provide a bearing structure for a spindle which is of the type as described in the beginning and eliminates the disadvantages of the known structures as mentioned above, may be produced very easily and at a low cost and insures that the center shaft of the spindle will be accurately centered at all times.

For attaining this object, the present invention provides that the mentioned centering tube, the upper part of which is mounted in the bearing housing in the vicinity of the collar bearing and the lower part of which contains and carries at least the part of the footstep bearing which is adapted to take up the radial pressures of the lower end of the center shaft, is made of a suit-' able plastic. lt has been found that such tubes of plastic may be produced at a very low cost and that, if they are made of a suitable kind of plastic and are properly designed and mounted, they have a' very low inertia in the transmission of vibrations and therefore do not impair the effect of the damping means and the good running features of the spindle but might even improve the same. The advantages of such a plastic tube are very prominent especially if this tube is not subjected at all or only slightly to stresses by the center shaft in the axial direction. For spindles of a certain type of construction the present invention provides that the upper end of the plastic tube is tightly secured in and by the bearing head of the collar bearing or by the bearing housing. The plastic tube then acts as a centering element and it considerably absorbs the vibrations of the center shaft. For securing the upper end of the plastic tube in a fixed position, it is of advantage to provide this end with a screw thread and to screw it tightly into a corresponding inner thread in the bearing head. The plastic tube may thus be very easily installed and then does not require any additional means for preventing it from twisting or for securing it in its longitudinal direction. The upper end of the plastic tube may, however, also be guided only in radial directions and so as to be pivotable. Although a plastic tube of this type usually requires additional centering means, it has considerable advantages due to its inexpensive manufacture and the properties of the plastic of absorbing vibrations. A very advantageous manner of mounting the plastic tube consists in providing its upper part with suitable projections which engage into corresponding apertures in the bearing head in which the collar bearing is mounted. Similar advantages may be attained if such projections on the plastic tube engage into corresponding apertures which are provided in a spacing tube which is interposed. between the collar bearing and the damping element and is mounted in a fixed position in the bearing housing. Such a construction permits the spacing tube to be very easily inserted and removed and it protects the plastic tube from twisting. The plastic tube may also be securely held and guided in the bearing housing by utilizing its elastic properties, for example, by providing its upper part with an annular bead which engages into a corresponding annular groove in the bearing head or in the bearing housing or by reversing this arrangement by providing the annular groove in the outer surface of the upper part of the plastic tube and the annular bead on the inner wall surface of the bearing head which is preferably stamped of sheet metal. If the footstep bearing or at least the part thereof which is adapted to take up the radial pressures of the lower end of the center shaft is to be firmly connected to the plastic tube, such a firm connection may be attained, for example, by molding the plastic tube over this bearing or bearing part. Further structural advantages may be attained by providing the plastic tube with shoulders or the like which are adapted to limit the axial movements of the damping element in one or both directions. For attaining a good circulation of lubricant within the bearing housing, it is of advantage to provide the plastic tube with one or more apertures, preferably above the damping element, to serve as passages for the lubricant.

The features and advantages of the present invention will become further apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings, in which FIG. 1 shows partly a side view and partly a longitudinal section of a bearing structure according to a first embodiment of the invention;

FIG. 2 shows a cross section which is taken along the line II II of FIG. 1;

FIG. 3 shows an enlarged longitudinal section of the upper part of the bearing structure as shown in FIG. 1;

FIG. 4 shows partly a side view and partly a longitudinal section of a bearing structure according to a second embodiment of the invention;

FIG. 5 shows a view similar to FIG. 4 of a bearing structure according to a third embodiment of the invention;

FIG. 6 shows a view likewise similar to FIG. 4 of a bearing structure according to a fourth embodiment of the invention;

FIG. 7 shows a cross section which is taken along the line VII VII of FIG. 6;

FIG. 8 shows partly a side view and partly a longitudinal section of the upper part of a bearing structure according to a further embodiment of the invention; while FIG. 9 shows a similar view, but of a modification of the bearing structure as shown in FIG. 8.

FIGS. I to 3 of the drawings illustrate the center shaft 1 of a spindle which is mounted in a bearing housing 3 in which the upper part of the center shaft is mounted in a collar bearing 2 which consists of a roller bearing and is mounted in a socketlikc bearing head 2a, while the lower end of the center shaft 1 is mounted in a footstep bearing which consists ofa bushing 4 and a bearing plate 4a. Bushing 4 which consists of a suitable bearing material, for example, hardened steel or bronze, is tightly fitted into the lower end of a tube 5 of plastic the upper end of which is tightly pressed into the bearing head 2a of the collar bearing 2, which head, in turn, is pressed into the housing 3. Between the bearing head 2a and the damping element 7 which may consist, for example, of a spirally wound coil of a conventional type which is immersed in oil, a slotted spacing tube 8 is provided which is held in an axially fixed position in the housing 3 and prevents any axial displacement of the damping element 7 in the upward direction. The plastic tube 5 is provided with radial projections 5a which engage into corresponding apertures 8a in the spacing tube 8 and prevent the latter from shifting in its axial direction and permit the spacing tube together with the plastic tube 5 to be installed in or removed from the housing 3 very easily as a unit. For securing the plastic tube 5 in the bearing head 2a also in a fixed position in the longitudinal direction, the plastic tube is provided with an annular bead 5c which engages into a corresponding annular groove 2c in the inner wall surface 2b of the bearing head 2a. This bead 5a may also be interrupted so as to render it more elastic. Since the bearing head 20 is slightly elastic as long as it is not installed and since the plastic tube 5 is likewise elastic, these two parts may also be easily slipped into or over each other despite the annular bead 5c. The damping element 7 between the plastic tube 5 and the wall of the housing 3 is embedded in a lubricant and absorbs and suppresses the radial vibrations of the center shaft 1. On its lower end, the plastic tube 5 is provided with an annular flange 5f which limits the position of the damping element 7 in the downward direction. Above the damping element 7, the plastic tube 5 is further provided with several radial apertures 5d through which the lubricant may easily pass or circulate which generally consists of a high-quality oil of a certain viscosity which also exerts a damping effect. The center shaft 1 is rotatable on and supported by the bearing plate 4a which may be mounted either in a fixed position or be movable in radial directions in housing 3 without, however, being rotatable therein. This bearing plate 4a is likewise provided with one or more apertures 4a, to form passages for the lubricant. The radial movements of the lower end of the rotating center shaft 1 necessarily result in corresponding deflecting movements of the lower part of the tube of plastic 5. The resilience of this tube, however, opposes the force of these radial movements of the rotating center shaft and returns the same to its properly centered position. The particular centering degrees which may he demanded of different spindles in view of their particular operating conditions and the size of these spindles may be controlled by making the plastic tube 5 of suitable dimensions and of a suitable material.

FIG. 4 illustrates a modification of the invention in which the upper end of the plastic tube 45 is secured directly to the inner wall surface of the bearing housing 43. The annular bead 45c which only projects for a short distance from the outer wall surface of the upper part of tube 45 engages into a corresponding annular groove 430 in the inner surface 43b of housing 43 and insures that the plastic tube 45 will be locked in a fixed position in its longitudinal direction. Tube 45 is further provided with a pair of shoulders 45e and 45f which limit the distance of the axial movement of the damping element 47 in both directions and combine this tube with the damping element into a structural unit which may be more easily installed in or removed from the housing 43. The bushing 44 of the footstep bearing is pressed into the lower end of the plastic tube 45 and its upper end abuts against a bead or flange 45g on the inner wall of this tube. Bushing 44 may, however, also be firmly combined with the plastic tube by molding the latter thereon.

FIG. 5 illustrates another modification of the invention in which the plastic tube 55 is pressed into a bearing head 52a of the collar bearing 52. This bearing head which may be stamped of sheet metal has an annular bead 52:1 on its inner surface which engages into a corresponding annular groove 550 in the outer surface of the plastic tube 55 and locks the latter in a fixed position in its longitudinal direction to the bearing head. Instead of providing the bearing head 52 with such an annular bead 52a this head may also be provided with several substantially pointed indentations. An annular shoulder 55g on the plastic tube forms a stop member against which the lower end of the bearing head 52a and the upper end ofa spacing tube 58 abut. The plastic tube 55 is further provided with projections 55a which engage into corresponding apertures 58a in the spacing tube 58 and prevent the latter from turning and from shifting longitudinally in the downward direction.

FIGS. 6 and-7 illustrate a further modification of the invention in which the footstep bearing 64 guides the rotating spindle 61 in both the axial and radial directions. The plastic tube 65 is molded over the footstep bearing, although the latter may also be pressed into the tube 65. In both cases it is advisable to provide the upper part of the outer surface of bearing 64 which is connected to the plastic tube with a knurling or the like. On its upper end, tube 65 is provided with projections 65a which engage into corresponding apertures 68a in a spacing tube 68 which is tightly pressed into the bearing housing 63 to a position intermediate the damping element 67 and the collar bearing 62 which is mounted directly in the housing 63. The interengaging projections 65a and apertures 68a prevent the plastic tube 65 tog'ether with the footstep bearing 64 from turning or twisting. The spacing tube 68 limits the axial movement of the damping element 67 in the upward direction. The outer surfaces 65b of the projections 65a on the plastic tube 65 engage without play with the inner wall surface of housing 63 without, however, exerting clamping pressures thereon. Tube 65 may therefore carry out radial movements at its lower end about these surfaces 65b without moving back to its central position due to its own resilience. It is therefore necessary to provide special centering means which in this embodiment of the invention consists on a so-called basket spring 69. This spring which is of a type which is known as such is secured to the bottom piece 63a of the housing 63 and is provided with slotted arms 69a which surround the footstep bearing 64 with a small radial clearance.'This bearing 64 is supported on a plate 69d and is movable thereon under pressure and friction when the lower end of the center shaft deflects in radial directions.

FIG. 8 shows another embodiment of the invention in which the collar bearing is again mounted in a bearing head 82a and the plastic tube 85 is provided with projections 85a which engage into corresponding apertures 82c in the bearing head 82a so that the plastic tube 85 is prevented from twisting or turning and from moving in its longitudinal direction.

The same effect may be attained according to FIG. 9 by providing the upper end of the plastic tube 95 with a male thread 95a which is tightly screwed into a corresponding female thread in the bearing head 92a.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

l. A spindle for a spinning or twisting machine comprising a bearing housing, a center shaft extending from above into said housing to a level near the lower end thereof and rotatable within said housing, a collar bearing secured in the upper part of said housing and surrounding and engaging with an upper part of said shaft for maintaining and guiding said upper part in a centered position relative to said housing during the rotation of said shaft, a footstep bearing disposed within the lower part of said housing and comprising first and second bearing parts, said first hearing part surrounding a lower part of said shaft and adapted to take up the radial pressures exerted during the rotation of said shaft by deflections of said lower shaft part from its central position, said second bearing part being adapted to take up the axial pressure exerted by said shaft due to its weight, and centering means comprising a tube of plastic of a certain inherent resilience within said housing underneath and axially spaced from said collar bearing having a relatively long upper part and a rela tively short lower part, said lower tube part surrounding and rigidly secured to and carrying at least said first bearing part, said long upper tube part surrounding and radially spaced from said shaft, at least the upper end portion of said upper tube part being at least nonrotatably connected to said housing, and a relatively long annular chamber within said housing around a section of said tube between said connected upper end portion and the lower end of said tube so that, when at least said first bearing part is deflected from its central position due to deflections of the lower end of said shaft during the rotation thereof, the lower part of said tube is movable in radial directions within said chamber, said centering means further comprising resilient damping means within said chamber and acting upon the lower parts of said tube so as to counteract said deflections.

2. A spindle as defined in claim 1, in which said upper end portion of said plastic tube is rigidly secured to said housing so that, due to the inherent resilience of said tube, said lower part thereof also resiliently counteracts said deflections.

3. A spindle as defined in claim 1, in which said housing comprises a tubular main housing and a separate socketlike head surrounding and carrying said collar bearing and having a tubular extension underneath said collar bearing inserted into the open upper end of said main housing and rigidly secured thereto, said upper end portion of said plastic tube being inserted into and rigidly secured to said extension so that said lower part of said tube carrying at least said first bearing part is resiliently movable in radial directions relative to said upper end portion of said tube.

4. A spindle as defined in claim 3, in which said tubular extension has a female thread and said upper end portion of said plastic tube has a male thread and is screwed into said female thread so as to be rigidly secured to said head of said housing.

5. A spindle as defined in claim 3, in which said tubu lar extension has radial apertures and said upper end portion of said plastic tube has radial projections engaging into said apertures.

6. A spindle as defined in claim 3, in which the upper part of said plastic tube has an annular groove in its outer wall surface and said socketlike head is made of sheet metal and its extension has a corresponding annular inwardly extending projection engaging into said groove.

7. A spindle as defined in claim 1, in which said upper end portion of said plastic tube is nonrotatably but pivotably connected to said housing, said centering means further comprising'additional spring means mounted on said housing and acting upon said lower end of said tube and at least upon said first bearing member for counteracting said deflections.

8. A spindle as defined in claim 1, further comprising a spacing tube secured to the inner wall of said housing underneath said collar bearing and having a lower end for limiting the axial moveability of said damping means in the upward direction, said spacing tube further having radial apertures, said upper end portion of said plastic tube having radial projections engaging into said apertures.

9. A spindle as defined in claim 1, in which underneath said collar bearing said upper part of said housing has an annular groove in its inner wall and said plastic tube has acorresponding annular projection on its upper end portion engaging into said groove.

10. A spindle as defined in claim 1, in which said plastic tube is tightly molded upon at least said first bearing part so as to be rigidly secured thereto.

11. A spindle as defined in claim 1, in which said in one axial direction.

12. A spindle as defined in claim 1, in which the wall of said plastic tube has at least one radial aperture, preferably above said damping means, to serve as a pasplastic tube has shoulder means on its outer surface for sage for a lubricant.

limiting the moveability of said damping means at least 

1. A spindle for a spinning or twisting machine comprising a bearing housing, a center shaft extending from above into said housing to a level near the lower end thereof and rotatable within said housing, a collar bearing secured in the upper part of said housing and surrounding and engaging with an upper part of said shaft for maintaining and guiding said upper part in a centered position relative to said housing during the rotation of said shaft, a footstep bearing disposed within the lower part of said housing and comprising first and second bearing parts, said first bearing part surrounding a lower part of said shaft and adapted to take up the radial pressures exerted during the rotation of said shaft by deflections of said lower shaft part from its central position, said second bearing part being adapted to take up the axial pressure exerted by said shaft due to its weight, and centering means comprising a tube of plastic of a certain inherent resilience within said housing underneath and axially spaced from said collar bearing having a relatively long upper part and a relatively short lower part, said lower tube part surrounding and rigidly secured to and carrying at least said first bearing part, said long upper tube part surrounding and radially spaced from said shaft, at least the upper end portion of said upper tube part being at least nonrotatably connected to said housing, and a relatively long annular chamber within said housing around a section of said tube between said connected upper end portion and the lower end of said tube so that, when at least said first bearing part is deflected from its central position due to deflections of the lower end of said shaft during the rotAtion thereof, the lower part of said tube is movable in radial directions within said chamber, said centering means further comprising resilient damping means within said chamber and acting upon the lower parts of said tube so as to counteract said deflections.
 2. A spindle as defined in claim 1, in which said upper end portion of said plastic tube is rigidly secured to said housing so that, due to the inherent resilience of said tube, said lower part thereof also resiliently counteracts said deflections.
 3. A spindle as defined in claim 1, in which said housing comprises a tubular main housing and a separate socketlike head surrounding and carrying said collar bearing and having a tubular extension underneath said collar bearing inserted into the open upper end of said main housing and rigidly secured thereto, said upper end portion of said plastic tube being inserted into and rigidly secured to said extension so that said lower part of said tube carrying at least said first bearing part is resiliently movable in radial directions relative to said upper end portion of said tube.
 4. A spindle as defined in claim 3, in which said tubular extension has a female thread and said upper end portion of said plastic tube has a male thread and is screwed into said female thread so as to be rigidly secured to said head of said housing.
 5. A spindle as defined in claim 3, in which said tubular extension has radial apertures and said upper end portion of said plastic tube has radial projections engaging into said apertures.
 6. A spindle as defined in claim 3, in which the upper part of said plastic tube has an annular groove in its outer wall surface and said socketlike head is made of sheet metal and its extension has a corresponding annular inwardly extending projection engaging into said groove.
 7. A spindle as defined in claim 1, in which said upper end portion of said plastic tube is nonrotatably but pivotably connected to said housing, said centering means further comprising additional spring means mounted on said housing and acting upon said lower end of said tube and at least upon said first bearing member for counteracting said deflections.
 8. A spindle as defined in claim 1, further comprising a spacing tube secured to the inner wall of said housing underneath said collar bearing and having a lower end for limiting the axial moveability of said damping means in the upward direction, said spacing tube further having radial apertures, said upper end portion of said plastic tube having radial projections engaging into said apertures.
 9. A spindle as defined in claim 1, in which underneath said collar bearing said upper part of said housing has an annular groove in its inner wall and said plastic tube has a corresponding annular projection on its upper end portion engaging into said groove.
 10. A spindle as defined in claim 1, in which said plastic tube is tightly molded upon at least said first bearing part so as to be rigidly secured thereto.
 11. A spindle as defined in claim 1, in which said plastic tube has shoulder means on its outer surface for limiting the moveability of said damping means at least in one axial direction.
 12. A spindle as defined in claim 1, in which the wall of said plastic tube has at least one radial aperture, preferably above said damping means, to serve as a passage for a lubricant. 